Advances technology in digital signal processing has led to high speed transmission of digital media content to the consumer via telephone, satellite, and coaxial cable networks. Theses advances enable media suppliers to provide hundreds of cable television channels to subscribers by packaging digitally store video (digital video), transmitting the compressed digital video over conventional coaxial cable television channels, and then presenting the video to the subscriber via a set top box (tuner and digital media recorder). The one of the fastest going component of this technology is video-on-demand. A system in which a subscriber communicates directly with a video service provider via a communication system (phone/cable/satellite) to request a video title from a video library; the requested video title is routed to the subscriber's home via a communication system for immediate or delayed viewing.
The viewer's selected media title is downloaded from the provider's archive and broadcasted over a communication network to the viewer's sit on top box. In General the system works by allowing the viewer to scroll through the lists of programs, selecting a program and forwarding that selection to the service provider such as disclosed in U.S. Pat. No. 5,357,276 issued Oct. 18, 1994 and U.S. Pat. No. 5,477,262 issued Dec. 19, 1995. Each request is answered with a single download to a requesting customer. Alternatively, large group downloads require the scheduling of downloadable/broadcast media programming several days to weeks in advance. There is no quick and easy way to provide small disperse group consumers true VOD without large bandwidth or long wait time.
A derivative of the Resource Interchange File Format (RIFF), is AVI (Audio Video Interleafs). Which divides a file's data into blocks, or “chunks.” Each “chunk” is identified by a FourCC tag. The composition of an AVI file takes the form of a single chunk in a RIFF formatted file, which is subdivided into two mandatory “chunks” and one optional “chunk”.
The first sub-chunk has an identifying tag that is called “hdrl”. Hdrl is the file header and contains metadata about the video, such as its frame rate, height and width. The second sub-chunk has an identifying tag that is called “movi” tag. This chunk contains the audio/visual data that make up the AVI movie. The third optional sub-chunk is identifying tag called “idx1”. This tag indexes the offsets of the data chunks within the file.
Using the RIFF format, the audio/visual data contained in the “movi” chunk can be encoded or decoded by software called a codec: an abbreviation for (en)coder/decoder. The codec of a file is utilized for translates between raw data and the (compressed) data format used inside the movi chunk. An AVI file is very versatile, it can carry audio/visual data inside the chunks in virtually any compression scheme, including Full Frame (Uncompressed), Cinepak, Motion JPEG, Editable MPEG, MPEG-4 Video, VDOWave, ClearVideo/RealVideo, QPEG, and Intel Real Time (Indeo).
Media file are normally viewed at a rate of 30 frames per second. The transmission of large media file is facilitated by subdividing the large file into several smaller files that can be easily transmitted over a network and re-assemble at a destination. The smaller the file size, the easier it is for a network to manage the transmission the file without experiencing difficulties. Flow control, ease at which files move over a network, is affected by the size of a file. The bigger the file, more time and resources of the network over which it is being transmitted must be invested in the file's transmission. The bigger the file, the more buffer space must be used to store the contents (data) contained within file within the network as it is being transmitted.
The size of a media file has increase in size as the visual destiny (resolution) of media displaying device increase. We when from Standard-Definition TV, to Enhanced-Definition TV, and now we have High-Definition TV. The frame rate of a media file may remain the same (30 frames per seconds), but the size of each frame has increased several folds. A two-hour HD movie can easily more than 2 times the size of a two-hour Standard-Definition TV movie file. This increase content means that we will need to move more bigger media file faster, if we are to fully utilize the newly available High Definition viewing.
Data Stream on a cable network has multiple channels that simultaneously carry multiple media programs. The channels are can be generated by employment of Time Divided Multiplexing (TDM) technology. A consumer can selectively pick out a program by tuning to/selecting a specific channel on the cable network; pulling out a desired media program from the stream of multiple programs being transmitted. Multiplexing can also be Frequency Divided (FDM). Both techniques will allow for subdividing of bandwidth into channels that can be used to carry multiple downloads from a single source point on a network.
The Data Stream on a cable network can be composed of media from several different media sources that share the cable networks abilities to transmit, download media, to consumers. In a fair use application of the network resources, each supplier/channel will has equal access to the networks resources (ability to download media to customers).
In a multi-user network environment, all users should be allocated the same amount of network resources. If the network has R amount of resources and N number of users, then an equitable distribution would be R/N. In a closed network system, finite resources, each user would be allocated equal amount of data transmission opportunity: if fair or best effort. A media supplier is a company that provides downloadable media that can be viewed over a network (i.e. Satellite, Cable, Telephone, Broadcast Radio Waves). Each Media Suppliers (MS) that subdivide its 10 Kbytes per cycle into 10 sub-channels will be able to simultaneously transmit up to ten (10) media program.
Each second will constitute a cycle in the fair use of the network resources (ability to transmit/download media to customers). If a network has the ability to transmit 60 Kilobyte of data per second (60 Kbytes/sec) and there are six (6) MS supplying media programming. Then a fair use of the network would be 10 Kbytes/seconds per user (60 Kbytes/6 per seconds), or 10 Kbytes per 0.16667 seconds. Each MS supplier can subdivide their 10 Kbytes/0.16667 seconds into ten (10) 1 Kbytes sub-channels (each 1 Kbytes having a duration of 0.01667 seconds, enabling them to simultaneously transmit 10 media files at the same time on 10 distinct channels.
When a MS transmits a media file, the size of the file will determine how much of the networks resources it will consume. If one the MS transmit a file bigger than the fair use allotment (i.e. 11 Kbytes), then one of the other MS suppliers will not be able transmit the files that they were planning to transmit. Trying to transmit more data (content) than the network can handle, is similar to pouring 61 ounces into a container that hold 60 ounces. The attempt will excess the networks capacity and result in the lost of data that is being transmitted/downloaded on the network. Over usage will result in congestions, and congestion will lead to lost of data, and a need to re-transmit lost data will lead to more congestion that can lead to more data lost, or slowing of the data transmission process. A network try to compensate for data lost by re-transmitting the original content, but this adds to the load on the network, and further delay the transmission-reception of the data (content) to the consumer.
One method for facilitating the transmission of a Large Media File is to sub-divide the file into several smaller files that can be easily transmitted over a network and re-assemble at a destination. The smaller the file size, the easier it is to fit the file into a transmission channel and not exceed the fair use allotment of the MS provider.